A Degree In Happiness

Back in 2015, Tal Ben-Shahar was on a transatlantic flight when a question came to mind: How is it that there is a field of study for psychology, philosophy, history, medicine, geography, you name itand there is no field of study for happiness? Yeah, there is positive psychology but that's just the psychology of happiness. What about what philosophers like Lao Tzu or Aristotle had to say about it? What about what literature remarked on happiness? Or neuroscience or theology or economics? Why isn't there an interdisciplinary field of study that looks at life's ultimate highest goal?